• Korean Journal of Environmental Biology
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• v.29 no.3
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• pp.154-161
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• 2011

The species diversity of Betaproteobacteria in the Sumunmulbengdui Wetland Area of Jeju Island was studied using culture based techniques, and candidates for novel taxa were screened. Twenty two novel bacterial strains belonging to Betaproteobacteria were isolated, which could be assigned to 16 genera of 4 families, namely Burkholderiaceae (3 strains), Comamonadaceae (8 strains), Oxalobacteraceae (5 strains), Neisseriaceae (5 strains), and an unassigned group belonging to Burkholderiales (1 strain) based 16S rRNA gene sequences. The genus Chromobacterium contained three candidates of novel species, and each of the genera Burkholderia, Comamonas, Pelomonas and Herbaspirillum contained two candidates respectively. Through the analysis of membrane fatty acid profiles and physiological properties using API 20NE as well as morphological and cultural properties, each of the isolates was found to form potentially novel species. Brief description of 22 potential candidates for new species or subspecies is given accordingly.

• Journal of Environmental Impact Assessment
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• v.29 no.5
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• pp.363-376
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• 2020

Various policies and institutional efforts are being made for mature democracy and more sustainable administration of our society. In this respect, the importance of civic participation, considered essential in environmental impact assessment, has been consistently emphasized in the relevant theories and practices. Although various methods and forms of public participation are taking place in Korea, criticism is widely understood that collecting citizens' opinions in the decision-making process has become ineffective and formal. Starting from these issues, this paper seeks to learn lessons from the foreign cases in the international context. Extensive literature review was conducted to examine the meaning and objectives of public participation in EIA and the tactical principles. Based on this, the participatory systems and procedures in the United States, Britain, Germany, Japan, and Canada were critically reviewed, and the implications were derived through specific cases. The results are, first, the provision of specific public participation guidelines, second, the securing of transparency in the decision-making process, third, the expansion of procedural participation levels, and lastly, the guarantee of participation opportunities. This paper is meaningful as a basic study to enrich discussions on public participation in the domestic EIA hoping to help research through more diverse empirical cases in the future.

• Journal of the Korean Chemical Society
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• v.58 no.4
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• pp.393-405
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• 2014

The purpose of this study was to investigate the characteristics of social interaction on cultural aspects, verbal interaction, and discussion maps in scientific modeling instruction on combustion in middle school. Revised-CLEQ (Cultural Learning Environment Questionnaire), verbal interaction framework, discussion maps analysis were implemented for this study. The results of study follow respectively. First, the characteristics on cultural aspects of middle school students showed cooperation rather than competition in terms of collectivism. Students' attitudes to learning science tended to depend on others' idea, and students were passive and reluctant to present their comments when they were modeling work. Second, for the characteristics of verbal interaction, they simply presented knowledge related to build a model. The response to comments and feedback was relatively few. Third, discussion maps showed a lot of interaction for reponses that was alternatively brought the concept of commenters, which students were depended on a specific one, and responses. There were not many interaction for elaboration, which were described to have new presented ideas, corrections, and reasons when they exchange their ideas. In this study the model type of interaction affecting the formation of the students understanding of and in our country, it makes a lot of social interactions as the basis for teaching system could be utilized.

• Journal of Life Science
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• v.26 no.4
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• pp.398-405
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• 2016

Statins, the inhibitors of 3-hydroxy 3-methylglutaryl coenzyme A (HMG-CoA) reductase, are widely used in treatments of hypercholesterolemia and newly known as anti-cancer effect of various cancer cells. Recently, several studies suggested that reactive oxygen species (ROS) play a critical role on cell death signaling. However, mechanism of ROS by rosuvastatin is currently unclear. This study aimed to explore the molecular mechanism of apoptosis by rosuvastatin in human prostate cancer PC-3 cells. Cell viability and apoptosis-related protein expression were measured by MTT assay and western blotting, respectively. In addition, the levels of apoptosis and ROS were analyzed. The results showed that rosuvastatin dramatically reduced cell viability in a dose- and time-dependent manner. We confirmed that rosuvastatin induced apoptosis through reduction of procaspase-3 and cleavage of poly (ADP-ribose) polymerase (PARP) in PC-3 cells. In addition, rosuvastatin stimulated ROS production in a dose-dependent manner and pre-treatment with N-acetylcysteine (NAC), a ROS scavenger, significantly recovered rosuvastatin-induced ROS and apoptosis. Thus, we concluded that rosuvastain induces apoptosis through generation of ROS in human prostate cancer PC-3 cells and provides a promising approach to improve the efficacy of cancer therapy.

• The Journal of Korean Academy of Prosthodontics
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• v.55 no.3
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• pp.251-257
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• 2017

Purpose: The purpose of this study was to evaluate whether the internal abutment length affected screw stability in an internal connection implant. Materials and methods: Twenty long internal connection implants (Replus system, $4.7{\times}11.5mm$) were selected for this investigation. Abutments were assigned to four groups depending on the length of the internal connection (abutments with internal lengths of 1, 2, 3, and 4 mm, respectively). Each implant fixture specimen was embedded in resin medium and connected to an abutment with an abutment screw. A load of 100 N, applied at an angle of $30^{\circ}$ to the long axis of the implant, was repeated for $1.0{\times}10^6$ cycles. Reverse torque values (RTV) were recorded before and after loading, and the change in RTV was calculated. Data were analyzed with the Kruskal-Wallis test. Results: The change in RTV was not significantly different among the groups (P>.05). Screw loosening and fractures were not observed in any groups, and joint stability was maintained. Conclusion: The internal length of the abutment may not significantly affect the degree of screw loosening.

• KDI Journal of Economic Policy
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• v.27 no.1
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• pp.1-38
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• 2005

Our paper aims to estimate a household consumption function in the presence of liquidity constraints as well as household characteristics. Empirical findings from a Korean cross-sectional data (National Survey of Household Income and Expenditure) reveal that several family characteristics, such as household size, number of working members, children in school, and educational level and age of the household head, turn out to be critical determinants of household consumption. Especially, the influence of household size on consumption decision is shown to be highly significant, not only indirectly through its impact on household income, but also directly by affecting the household's preference for consumption itself. While, the other family characteristics primarily influences household income. Our paper distinguishes itself from existing literature in that it greatly improves the explanatory power of the estimated household consumption function by measuring the degree of the liquidity constraint rather than simply identifying its presence. Based on the assumption that the present value of human capital is a function of household characteristics, the degree of the liquidity constraint is represented by the underestimated portion of the human capital. Such a method of implementing the liquidity constraint is useful in treating various types of assets according to their liquidity. Finally, our estimated household consumption function is applied to decompose cross-sectional variances of consumption inequality. The analysis confirms that the overall alleviation in liquidity constraints in Korea after the 1997 currency crisis reduced consumption inequality despite the worsening of income inequality and changes in the demographic composition of family characteristics during the same period.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.159-159
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• 2017

스마트 시설환경은 대표적으로 원예, 축산 분야 등 여러 형태의 농업현장에 정보 통신 및 데이터 분석 기술을 도입하고 있는 시설화된 생산 환경이라 할 수 있다. 근래에 하드웨어적으로 급증한 스마트 시설환경에서 생산되는 방대한 생육/환경 데이터를 올바르고 적합하게 사용하기 위해서는 일반 산업 현장과는 차별화 된 분석기법이 요구된다고 할 수 있다. 소프트웨어 공학 분야에서 연구된 빅데이터 처리 기술을 기계적으로 농업 분야의 빅데이터에 적용하기에는 한계가 있을 수 있다. 시설환경 내/외부의 다양한 환경 변수는 시계열 데이터의 난해성, 비가역성, 불특정성, 비정형 패턴 등에 기인하여 예측 모델 연구가 매우 난해한 대상이기 때문이라 할 수 있다. 본 연구에서는 근래에 관심이 급증하고 있는 인공신경망 연구 소프트웨어인 Tensorflow (www.tensorflow.org)와 대표적인 Open source인 OpenNN (www.openn.net)을 스마트 시설환경 환경변수 상호간 상관성 분석에 응용하였다. 해당 소프트웨어 라이브러리의 운영환경을 살펴보면 Tensorflow 는 Linux(Ubuntu 16.04.4), Max OS X(EL capitan 10.11), Windows (x86 compatible)에서 활용가능하고, OpenNN은 별도의 운영환경에 대한 바이너리를 제공하지 않고 소스코드 전체를 제공하므로, 해당 운영환경에서 바이너리 컴파일 후 활용이 가능하다. 소프트웨어 개발 언어의 경우 Tensorflow는 python이 기본 언어이며 python(v2.7 or v3.N) 가상 환경 내에서 개발이 수행이 된다. 주의 깊게 살펴볼 부분은 이러한 개발 환경의 제약으로 인하여 Tensorflow의 주요한 장점 중에 하나인 고속 연산 기능 수행이 일부 운영 환경에 국한이 되어 제공이 된다는 점이다. GPU(Graphics Processing Unit)의 제공하는 하드웨어 가속기능은 Linux 운영체제에서 활용이 가능하다. 가상 개발 환경에 운영되는 한계로 인하여 실시간 정보 처리에는 한계가 따르므로 이에 대한 고려가 필요하다. 한편 근래(2017.03)에 공개된 Tensorflow API r1.0의 경우 python, C++, Java언어와 함께 Go라는 언어를 새로 지원하여 개발자의 활용 범위를 매우 높였다. OpenNN의 경우 C++ 언어를 기본으로 제공하며 C++ 컴파일러를 지원하는 임의의 개발 환경에서 모두 활용이 가능하다. 특징은 클러스터링 플랫폼과 연동을 통해 하드웨어 가속 기능의 부재를 일부 극복했다는 점이다. 상기 두 가지 패키지를 이용하여 2016년 2월부터 5월 까지 충북 음성군 소재 딸기 온실 내부에서 취득한 온도, 습도, 조도, CO2에 대하여 Large-scale linear model을 실험적(시간단위, 일단위, 주단위 분할)으로 적용하고, 인접한 세그먼트의 환경변수 예측 모델링을 수행하였다. 동일한 조건의 학습을 수행함에 있어, Tensorflow가 개발 소요 시간과 학습 실행 속도 측면에서 매우 우세하였다. OpenNN을 이용하여 대등한 성능을 보이기 위해선 병렬 클러스터링 기술을 활용해야 할 것이다. 오프라인 일괄(Offline batch)처리 방식의 한계가 있는 인공신경망 모델링 기법과 현장 보급이 불가능한 고성능 하드웨어 연산 장치에 대한 대안 마련을 위한 연구가 필요하다.

• Applied Biological Chemistry
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• v.50 no.3
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• pp.228-232
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• 2007

This study was performed to investigate the cytotoxic activity from Vitex rotundifolia. V. rotundifolia was extracted with methanol, ethanol, and acetone, and then the cytotoxic effect of these extracts was measured by the MTT reduction assay and morphological assay on the HT-29 human colon carcinoma cells. Among the three extracts, the acetone extract showed the highest cytotoxic activity on the HT-29 cells in a dose-dependent manner with an $IC_{50}$ value of 10 ${\mu}g/ml$. The acetone extract was further fractionated sequentially with n-hexane, diethyl ether, ethyl acetate, and water layer according to the degree of polarity. The n-hexane layer among the fractioned layers showed inhibitory activity on the growth of HT-29 cells. In addition, n-hexane layer also showed the cytotoxic activity against SW620 human colon carcinoma cells. These result indicated that extracts of V. rotundifolia may contain bioactive materials and could be potential candidates as chemotherapeutic agents against human colon carcinoma cells.

• Journal of The Korean Association of Information Education
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• v.1 no.1
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• pp.38-48
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• 1997

This study is an attempt to present a usage of the Web as CAI in the classroom and to give a direction to the future education in the face of information age. Characteristcs of information society, current curriculum, educational and teacher education are first analyzed in this article. The features of internet and 'Web are then summarized to present benefits of usage in the classroom as a CAI tool. The literature shows several characteristics of information society as follows : a technological computer, a provision and sharing of information, multi functional society, a participative democracy', an autonomy, a time value..A problem solving and 4 Cs(e.g., cooperation, copying, communication, creativity) are newly needed in this learning environment. The Internet is a large collection of networks that are tied together so that users can share their vast resources, a wealth of information, and give a key to a successful, efficient. individual study over a time and space. The 'Web increases an academic achievement, a creativity, a problem solving, a cognitive thinking, and a learner's motivation through an easy access to : documents available on the Internet, files containing programs, pictures, movies, and sounds from an FTP site, Usenet newsgroups, WAIS seraches, computers accessible through telnet, hypertext document, Java applets and other multimedia browser enhancements, and much more, In the Web browser will be our primary tool in searching for information on the Internet in this information age.

• Journal of The Korean Association of Information Education
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• v.21 no.4
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• pp.451-462
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• 2017

This study selected 3D printing that is highly likely to be adopted in schools. This research was conducted in two stages: 1) proposing the learning activity framework for utilizing 3D printing in education, and 2) exploring the potential of integrating 3D printing in the school field. The '3D printing learning activity framework' proposed in this study includes four phases that are categorized according to the complexity of problem-solving processes and collaborative interaction: Step 1 as production through replication, Phase 2 as means of imaginary expression, Phase 3 as near problem-solving, and Phase 4 as expanded problem-solving. Next, we conducted the field study with 23 students in the 6th grade math class where they learned the various solid shapes and volumes through 3D printing-integrated activities. The lesson was considered as Phase 1, which is the production through replication. Overall, the results showed that the participants had positive perceptions about the efficacy of 3D printing activities, the quality of learning experience, and satisfaction. On the other hand, it was found that the usability of 3D printers and CAD program needs further improvement The contribution of this study can be found in the learning activity framework that can guide 3D printing activity design in school, and in the exploration of enhancing the connection between 3D printing activities and curricular relevance beyond simple interest toward a novel technology.